Ok after listening to music for awhile when I unlock the player sometimes the screen stays black and doesn't turn back on until I reset it. Does anyone know how to fix this. And whenever I have the sd card in my player it doesn't turn on. Anyone know how to fix that? any help is appreciated.

Ok after listening to music for awhile when I unlock the player sometimes the screen stays black and doesn't turn back on until I reset it. Does anyone know how to fix this. And whenever I have the sd card in my player it doesn't turn on. Anyone know how to fix that? any help is appreciated.